The invention relates to a method for the manufacture of a catheter such as a nephrostomy drainage catheter or any other catheter, comprising (1) the extrusion from flexible plastic of a tubular basic catheter body with a central channel or lumen, (2) the attachment to one end of the basic body of a coupling element or hub, (3) the deformation of the opposite end part into a curved form, and (4) the providing in the curved end part of a number of side-openings connecting the central channel to the outside.
A drainage catheter, in particular a nephrostomy catheter, manufactured according to this per se known method is placed into an elastic, deformed and straightened state for insertion into the patient. The known drainage catheters of this type have the drawback that they can have only small discharge openings, because otherwise the wall in the vicinity of the side-openings may form sharp, outer ridges. When the side-openings are arranged in the end part, for example by punching while the latter is in the curved form, sharp ridges occur when straightening takes place. When the openings are punched in the straightened form of the catheter tip, the wall buckles sharply outward in the curved state of the catheter end.
Since a sharply buckled wall portion causes danger of injury either when it is being inserted into the patient or in the inserted position, it is necessary to avoid this buckling. Thus only small side-openings are used. The drainage capacity of the catheter is however limited as a result, and small drainage openings are moreover more easily obstructed by a blockage.
The invention now has for an object a method for the manufacture of a drainage catheter as described above, whereby larger side-openings can be employed without the danger of buckling of the wall in the vicinity of these side-openings.